Study of the Left Ventricular Performance During Sequential and Ventricular Pacing by Quantitative Two Dimensional Echocardiography

Summary

The purpose of our work is to evaluate the response of the left ventricular end-diastolic volume (EDV), stroke volume (SV), ejection fraction (EF), and blood pressure (BP), to sequential (S), and ventricular (V) pacing. Five patients, two women and three men, aged 74 ± 3 (mean ± 1 SD) years, were studied by quantitative two dimensional echocardiography (Q2DE) during S and V at 80, 100 and 120 beats/min. EDV, SV, and EF were calculated using Simpson’s Rule on a four chamber view. Samples of 3 to 10 (mean 5) volumes were obtained at each rate for the two pacing modes. The results at 80-100-120/min are for EDV: 95-95-78 ml in S (p = 0.01),76-75-70 ml in V (NS). For SV: 58-58-44 ml in S (p = 0.05), and 46-43-38 ml in V (NS). EDV is higher in S at 80 (p = 0.02), and 100/min (p = 0.05); SV is higher in S at each frequency (p = 0.02). EF is unaffected by frequency and pacing mode. BP is unchanged with frequency, buth higher in S at 80 and 120/min. We conclude that Q2DE is a promising tool to study the hemodynamic effects of pacing. In patients with normal or subnormal EF, the hemodynamic advantages of sequential pacing are better filling and better SV of the LV, without change of EF.

With the technical assistance of I. Deboeck.